[amsat-bb] 24 Ghz stats
howied231 at hotmail.com
Thu Jul 2 13:00:13 PDT 2009
In response to Joe, W9SBD, at 24 Ghz:
6' antenna = 51 dB gain, 3dB BW = .4 deg, EIRP @1W = 126 KW
4' antenna = 48 dB gain, 3dB BW = .6 deg, EIRP @1W = 63 KW
18" antenna = 39 dB gain, 3dB BW = 1.6 deg, EIRP @1W = 8 KW
All figures rounded to next whole number, gains assume 65% efficiency.
We have excellent space allocations at 3.4 GHz for downlink that would be
very inexpensive to build. Even a high end 30 deg./K LNB with external 10
MHz. reference is less than $500 new and will convert 3.4 Ghz to 950 Mhz.
The used price is much lower. I have sketched out some ideas to compensate
and downconvert a really cheap ($50) DRO LNB to a 432 MHz. IF using mostly
off the shelf parts. This band is great for space comms and can use very
inexpensive commercial parts. There is very little terrestrial activity to
worry about and this band is not allocated for commercial downlinks in this
region. In areas where it is allocated, the frequencies below 3.410 don't
seem to be popular commercially.
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